In OFDM (Orthogonal Frequency-Division Multiplexing) system communication, input signals are subjected to subcarrier modulation, and the modulated signals are subjected to IFFT (Inverse Fast Fourier Transformation), thereby generating baseband signals. Therefore, if the size of FFT (Fast Fourier Transformation) increases due to the increased number of subcarriers, baseband signals with high peaks are generated, making PAPR (Peak-to-Average Power Ratio) high. The high PAPR may distort transmission signals due to characteristics of an amplifier at transmission side, degrading BER (Bit Error Rate). Therefore, arts to reduce PAPR in a multicarrier communication such as OFDM have been developed.
In an orthogonal frequency division multiplexing communication device disclosed in Unexamined Japanese Patent Application Kokai Publication No. 2006-165781, in order to reduce PAPR, prior to performing IFFT, the phase of a subcarrier modulated signal is controlled based on an optimal phase calculated by a sequential decision procedure.
Even if processing to reduce PAPR is performed, transmission signals may be distorted due to characteristics of an amplifier at transmission side, degrading BER. Effects such as noise in a transmission path may further degrade BER.